Chat. XXXVT.] 
\A(;run : ramdongri. 
865 
4. Riimdongpi. 
(Central Provinces Prospecting Syndicatk.) 
(Sec Plate 24.) 
The geology of the hills to the east of the Kanhftn river, stretching 
from Ramdongri H. S. to the big mass of quartzite I have called the 
Kuthulna hills, is very intricate and difficult to unravel, owing to thick 
jungle. 
The map of this area shown in Plate 24 was constructed after a very 
careful examination of the ground during which practically every 
exposure was visited. Tn many places the ground is obscured by debris 
or jungle so that it is very difficult to join up the various outcrops. 
The result shown on the map is such as to suggest an intrusive relation of 
the manganese-silioate-rocks with regard to the quartzites, schists, and 
gneisses. It should be noted, however, that the long thin band of raan- 
ganiferous rock shown as running in a east-north-east direction from the 
river-bank was not actually seen to connect with the mass of manganese- 
silicate-rock forming hill 5. Instead of so connecting it may have thinned 
out in lenticular fashion a little before. The apparent bifurcation 
at its eastern end of the mass of manganese-silicate-rock forming hill 5 
certainly suggests, most strongly, intrusive relations to the other rocks. 
This bifurcation may, however, be the effect of faulting. 
It was largely on the evidence of this occurrence, however, that the 
theory was put forward, doubtfully it is true,i that the manganese-sUicate- 
rocks of the Central Provinces are, like those of Vizagapatam, to be 
regarded as igneous intrusives; and if this were the only occurrence of such 
rocks it would be difficult to confute this theory. A careful study of 
the many other occurrences of these rocks has, however, as described 
earlier (page 315), pointed irresistably to the conclusion that the man- 
ganese-silicate-rocks of the Central Provinces are metamorphosed sedi- 
ment?. When the Ramdongri deposits have been opened up much more 
than at present, it may become possible to explain how the manganese- 
silicate-rocks of Ramdongri simulate igneous rocks in their relations to 
the quattzites, gneisses, and schists, and yet are, as they must be, con- 
sidering their similarity to the other manganese-silicate-rocks of the 
Central Provinces, really chemically- altered metamorphosed sediments. 
The Ramdongri mass of hills rises at Ramdongri H. S. to about 280 
feet above the surrounding alluvial country. AW the hills and hillocks 
owe their elevation either to quartzites, more or less micaceous, or to 
manganese-ore bodies, while the lower lying ground is occupied by m.ica- 
schists, biotite-gneisses, and tourmaline-granites. The various bands of 
1 Bee. G. S. I., XXXIII, p. 97, (1906); Trains. Min. Qeol. Inst Ind., I, p. 91, (1906 ) 
